UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 82
Manufacturer Part Number
4 BIT SINGLE-CHIP MICROCOMPUTER
(3) Functions of serial interface (channel 0) registers
(a) Serial operation mode register 0 (CSIM0)
Fig. 4-40 shows the format of serial operation mode register 0 (CSIM0).
CSIM0 is an 8-bit register which specifies a serial interface (channel 0) operation mode, serial clock,
wake-up function, and so forth.
CSIM0 is manipulated using an 8-bit memory manipulation instruction. The higher three bits can be
manipulated bit by bit. Each bit can be manipulated using its name.
Each bit may or may not allow read and/or write operation. (See Fig. 4-40.) Bit 6 allows bit test
operation only; any data written to this bit is invalid.
A RESET input clears all bits to 0.
Remark (R) : Read only
(W) : Write only
Fig. 4-40 Format of Serial Operation Mode Register 0 (CSIM0) (1/3)
Serial interface operation enable/disable specification bit (W)
Signal from address comparator (R)
Wake-up function specification bit (W)
Serial interface operation mode selection bit (W)
Serial clock selection bit (W)